scholarly journals Microscale diffusiophoresis of proteins

2020 ◽  
Author(s):  
Quentin Peter ◽  
Raphaël Jacquat ◽  
Therese Herling ◽  
Pavan Challa ◽  
Tadas Kartanas ◽  
...  
Keyword(s):  
Colloidal Particles ◽  
Chemical Potential ◽  
Living Systems ◽  
Spatial Organisation ◽  
Spatial Gradients ◽  
Molecular Scale ◽  
A Cell ◽  
Transport Effects ◽  
Biological Functionality

Abstract Living systems are characterised by their spatially highly inhomogeneous nature which is susceptible to modify fundamentally the behaviour of biomolecular species, including the proteins that underpin biological functionality in cells. Spatial gradients in chemical potential are known to lead to strong transport effects for colloidal particles, but their effect on molecular scale species such as proteins has remained largely unexplored. Here we demonstrate with microfluidic measurements that individual proteins can undergo strong diffusiophoretic motion in salt gradients in a manner which is sufficient to overcome diffusion and lead to dramatic changes in their spatial organisation on the scale of a cell. Moreover, we demonstrate that this phenomenon can be used to control the motion of proteins in microfluidics devices. These results open up a path towards a physical understanding of the role of gradients in living systems in the spatial organisation of macromolecules and highlight novel routes towards protein sorting applications on device.

scholarly journals Equation of State of a Cell Fluid Model with Allowance for Gaussian Fluctuations of the Order Parameter

2020 ◽  
Vol 65 (12) ◽  
pp. 1080
Author(s):  
I.V. Pylyuk ◽  
O.A. Dobush
Keyword(s):  
Equation Of State ◽  
Order Parameter ◽  
Chemical Potential ◽  
Fluid Model ◽  
Repulsive Interaction ◽  
Collective Variables ◽  
Relative Temperature ◽  
A Cell ◽  
Supercritical Temperature

The paper is devoted to the development of a microscopic description of the critical behavior of a cell fluid model with allowance for the contributions from collective variables with nonzero values of the wave vector. The mathematical description is performed in the supercritical temperature range (T > Tc) in the case of a modified Morse potential with additional repulsive interaction. The method, developed here for constructing the equation of state of the system by using the Gaussian distribution of the order parameter fluctuations, is valid beyond an immediate vicinity of the critical point for wide ranges of the density and temperature. The pressure of the system as a function of the chemical potential and density is plotted for various fixed values of the relative temperature, both with and without considering the above-mentioned contributions. Compared with the results of the zero-mode approximation, the insignificant role of these contributions is indicated for temperatures T > Tc. At T < Tc, they are more significant.

CD38 as an immunomodulator in cancer

2020 ◽  
Vol 16 (34) ◽  
pp. 2853-2861
Author(s):  
Yanli Li ◽  
Rui Yang ◽  
Limo Chen ◽  
Sufang Wu
Keyword(s):  
Multiple Myeloma ◽  
Cell Activation ◽  
Human Tissues ◽  
Transmembrane Glycoprotein ◽  
Cell Activation Marker ◽  
Research Findings ◽  
A Cell ◽  
And Function ◽  
Human Molecule

CD38 is a transmembrane glycoprotein that is widely expressed in a variety of human tissues and cells, especially those in the immune system. CD38 protein was previously considered as a cell activation marker, and today monoclonal antibodies targeting CD38 have witnessed great achievements in multiple myeloma and promoted researchers to conduct research on other tumors. In this review, we provide a wide-ranging review of the biology and function of the human molecule outside the field of myeloma. We focus mainly on current research findings to summarize and update the findings gathered from diverse areas of study. Based on these findings, we attempt to extend the role of CD38 in the context of therapy of solid tumors and expand the role of the molecule from a simple marker to an immunomodulator.

Autopoiesis and evolution: the role of organisms in natural drift

2021 ◽  
pp. 105971232110306
Author(s):  
Vincenzo Raimondi
Keyword(s):  
Living Systems ◽  
Explanatory Framework ◽  
Alternative Framework ◽  
Natural Drift ◽  
Genetic Reductionism ◽  
Development And Evolution

Genetic reductionism is increasingly seen as a severely limited approach to understanding living systems. The Neo-Darwinian explanatory framework tends to overlook the role of the organism for an understanding of development and evolution. In the current fast-changing theoretical landscape, the autopoietic approach provides conceptual distinctions and tools that may contribute to building an alternative framework. In this article, I examine the implications of the theories of autopoiesis and natural drift for an organism-centered view of evolution. By shifting the attention from genes to ontogenetic organism-niche configurations and their transformations over generations, this approach presents a compelling perspective on the role of organismal behavior in guiding phylogenetic drift.

scholarly journals PapRIV, a BV-2 microglial cell activating quorum sensing peptide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yorick Janssens ◽  
Nathan Debunne ◽  
Anton De Spiegeleer ◽  
Evelien Wynendaele ◽  
Marta Planas ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cell Model ◽  
Dependent Manner ◽  
Communication Signals ◽  
Gram Positive Bacteria ◽  
A Cell ◽  
Gastro Intestinal Tract

AbstractQuorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction.

Noncommutative scalar field in de Sitter space–time and pair creation process

2021 ◽  
Vol 36 (02) ◽  
pp. 2150011
Author(s):  
Nabil Mehdaoui ◽  
Lamine Khodja ◽  
Salah Haouat
Keyword(s):  
Scalar Field ◽  
Chemical Potential ◽  
De Sitter Space ◽  
Space Time ◽  
Pair Creation ◽  
De Sitter ◽  
Creation Process ◽  
Scalar Particles ◽  
Constant Electromagnetic Field

In this work, we address the process of pair creation of scalar particles in [Formula: see text] de Sitter space–time in presence of a constant electromagnetic field by applying the noncommutativity on the scalar field up to first-order in [Formula: see text]. We calculate the density of particles created in the vacuum by the mean of the Bogoliubov transformations. In contrast to a previous result, we show that noncommutativity contributes to the pair creation process. We find that the noncommutativity plays the same role of chemical potential and gives an important interest for studies at high energies.

scholarly journals A Role for the DnaJ Homologue Scj1p in Protein Folding in the Yeast Endoplasmic Reticulum

1998 ◽  
Vol 143 (4) ◽  
pp. 921-933 ◽  
Author(s):  
Susana Silberstein ◽  
Gabriel Schlenstedt ◽  
Pam A. Silver ◽  
Reid Gilmore
Keyword(s):  
Endoplasmic Reticulum ◽  
Unfolded Protein Response ◽  
Physiological Role ◽  
Carboxypeptidase Y ◽  
Reporter Protein ◽  
Unfolded Protein ◽  
A Cell ◽  
The Unfolded Protein Response ◽  
Protein Response

Members of the eukaryotic heat shock protein 70 family (Hsp70s) are regulated by protein cofactors that contain domains homologous to bacterial DnaJ. Of the three DnaJ homologues in the yeast rough endoplasmic reticulum (RER; Scj1p, Sec63p, and Jem1p), Scj1p is most closely related to DnaJ, hence it is a probable cofactor for Kar2p, the major Hsp70 in the yeast RER. However, the physiological role of Scj1p has remained obscure due to the lack of an obvious defect in Kar2p-mediated pathways in scj1 null mutants. Here, we show that the Δscj1 mutant is hypersensitive to tunicamycin or mutations that reduce N-linked glycosylation of proteins. Although maturation of glycosylated carboxypeptidase Y occurs with wild-type kinetics in Δscj1 cells, the transport rate for an unglycosylated mutant carboxypeptidase Y (CPY) is markedly reduced. Loss of Scj1p induces the unfolded protein response pathway, and results in a cell wall defect when combined with an oligosaccharyltransferase mutation. The combined loss of both Scj1p and Jem1p exaggerates the sensitivity to hypoglycosylation stress, leads to further induction of the unfolded protein response pathway, and drastically delays maturation of an unglycosylated reporter protein in the RER. We propose that the major role for Scj1p is to cooperate with Kar2p to mediate maturation of proteins in the RER lumen.

scholarly journals Potential role of SC1, a cell adhesion molecule, in mammary gland tumors

2008 ◽  
Author(s):  
Kenji Hagimori ◽  
Hidenori Kato ◽  
Keiko Fukuda ◽  
Masaharu Kikuta ◽  
Yasuhiro Tsukamoto ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Mammary Gland ◽  
Adhesion Molecule ◽  
Cell Adhesion Molecule ◽  
Potential Role ◽  
Mammary Gland Tumors ◽  
A Cell

scholarly journals The Protective Role of Dormant Origins in Response to Replicative Stress

2018 ◽  
Vol 19 (11) ◽  
pp. 3569 ◽  
Author(s):  
Lilas Courtot ◽  
Jean-Sébastien Hoffmann ◽  
Valérie Bergoglio
Keyword(s):  
Dna Replication ◽  
Mammalian Cells ◽  
Genome Stability ◽  
Replication Timing ◽  
Protective Role ◽  
Entire Genome ◽  
Replicative Stress ◽  
A Cell ◽  
The Many

Genome stability requires tight regulation of DNA replication to ensure that the entire genome of the cell is duplicated once and only once per cell cycle. In mammalian cells, origin activation is controlled in space and time by a cell-specific and robust program called replication timing. About 100,000 potential replication origins form on the chromatin in the gap 1 (G1) phase but only 20–30% of them are active during the DNA replication of a given cell in the synthesis (S) phase. When the progress of replication forks is slowed by exogenous or endogenous impediments, the cell must activate some of the inactive or “dormant” origins to complete replication on time. Thus, the many origins that may be activated are probably key to protect the genome against replication stress. This review aims to discuss the role of these dormant origins as safeguards of the human genome during replicative stress.

Modulation of vascular tone in renal microcirculation by erythrocytes: role of EDRF

1993 ◽  
Vol 264 (1) ◽  
pp. H190-H195 ◽  
Author(s):  
J. D. Imig ◽  
D. Gebremedhin ◽  
D. R. Harder ◽  
R. J. Roman
Keyword(s):  
Vascular Tone ◽  
Physiological Salt Solution ◽  
Nitric Oxide Synthase Inhibitor ◽  
Renal Microcirculation ◽  
Vasoconstrictor Response ◽  
A Cell ◽  
Afferent Arterioles ◽  
Synthase Inhibitor

The effect of erythrocytes (red blood cells, RBC) on vascular tone in the renal microcirculation was examined using the juxtamedullary nephron microvascular preparation perfused in vitro with a physiological salt solution containing 5% albumin. The basal diameters of the arcuate, interlobular, proximal, and distal afferent arterioles averaged 444 +/- 24, 74 +/- 3, 29 +/- 1, and 19 +/- 1 micron, respectively, when perfused with a cell-free solution at a pressure of 80 mmHg. The diameters of the arcuate and interlobular arteries increased by 14 +/- 4 and 13 +/- 4%, respectively, whereas the diameter of the proximal and distal portions of the afferent arterioles decreased by 7 +/- 2% when perfusion pressure was elevated from 80 to 160 mmHg. The addition of RBC to the perfusate reduced the basal diameters of interlobular and afferent arterioles by 11 +/- 4 and 15 +/- 3%, respectively. The maximal vasoconstrictor response was seen after the addition of only 1% RBC to the perfusate. Removal of platelets did not block the vasoconstrictor response to addition of RBC to the perfusate. The role of endothelium-derived relaxing factor (EDRF) in the vasoconstrictor response to RBC was studied by addition of nitric oxide synthase inhibitor, N omega-nitro-L-arginine (L-NNA, 100 microM) to the perfusate. L-NNA reduced the basal diameters of interlobular and afferent arterioles by 7 +/- 3 and 9 +/- 3%, respectively, and abolished the vasoconstrictor response to RBC. L-NNA had no effect on the pressure-diameter relationships of the preglomerular vasculature when added to perfusates already containing RBC.(ABSTRACT TRUNCATED AT 250 WORDS)

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